*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    background-color: #efedd6;
display: flex;
flex-direction: column;
align-items: center;
}
h1{
    margin: 10px;
}
.box{
   background: steelblue;
   width: 400px;
   height: 200px;
border-radius: 10px;
margin: 10px;
text-align: center;
line-height: 200px;
box-shadow: 2px 4px 5px rgba(0, 0, 0, .3);
/* js */
transform: translateX(400%);
transition: 0.4s ease-in-out 0;

}
.box:nth-of-type(even){
    transform: translateX(-400%);

}
.box.show{
    transform: translateX(0);
}
.box h2{
    font-size: 45px;
}